Presensitized plate for preparing lithographic printing plate

Abstract

A presensitized plate for preparing a lithographic printing plate comprises a substrate provided thereon with a light-sensitive layer containing a fluoro-aliphatic group-containing copolymer prepared by copolymerizing at least (A) an addition polymerizable monomer having, on a side chain, a fluoro-aliphatic group in which hydrogen atoms are replaced with fluorine atoms and (B) a (meth)acrylate having an ester chain represented by a specific general formula. The use of the foregoing specific fluorine atom-containing polymer permits the formation of a light-sensitive layer having uniform surface condition without causing abnormality in the surface quality due to the foaming phenomenon observed during the production and also permits the production of a positive light-sensitive resin composition having excellent solubility and dispersibility in a developer.

What is claimed is:  
     
       1. A presensitized plate for preparing a lithographic printing plate, which comprises a substrate provided thereon with a light-sensitive layer containing a fluoro-aliphatic group-containing copolymer prepared by copolymerizing at least the following monomers (A) and (B): 
       (A) an addition polymerizable monomer having, on a side chain, a fluoro-aliphatic group in which hydrogen atoms are replaced with fluorine atoms; and  
       (B) a (meth)acrylate having an ester chain represented by the following general formula (I) or (II):  
       
         
           CH 2 ═C(R 1 )—CO—O—R 2 —O—(CO—R 3 —O) n —R 4   (I)  
         
       
       
         
           CH 2 ═C(R 1 )—CO—(O—R 3 —CO) n —O—R 4   (II)  
         
       
       (In the formulas, R 1  represents —H or —CH 3 ; R 2  and R 3  each independently represents an alkylene group having 1 to 12 carbon atoms; R 4  represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, cycloalkyl group, aryl group, aralkyl group or heterocyclic group wherein the substituent on the group of R 4  is selected from the group consisting of alkyl or alkoxy group having 1 to 6 carbon atoms and n is a number ranging from 1 to 50). 
     
     
       2. The presensitized plate for preparing a lithographic printing plate of  claim 1 , wherein (A) the addition polymerizable monomer is a vinyl monomer carrying a radical polymerizable unsaturated group having, on a side chain, a fluoro-aliphatic group in which hydrogen atoms are replaced with fluorine atoms. 
     
     
       3. The presensitized plate for preparing a lithographic printing plate of  claim 2 , wherein the vinyl monomer is an acrylate or methacrylate compound represented by the general formula: Rf—R′—OOC—C(R″)═CH 2  (wherein R′ represents a single bond, an alkylene group, a sulfonamide-alkylene group or a carbonamide-alkylene group; R″ represents a hydrogen or halogen atom or a methyl group; and Rf represents a perfluoro-aliphatic group). 
     
     
       4. The presensitized plate for preparing a lithographic printing plate of  claim 1 , wherein R 2  and R 3  each independently represents an alkylene group having 2 to 6 carbon atoms, and R 4  represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms. 
     
     
       5. The presensitized plate for preparing a lithographic printing plate of  claim 3 , wherein R 2  and R 3  each independently represents an alkylene group having 2 to 6 carbon atoms, and R 4  represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms. 
     
     
       6. The presensitized plate for preparing a lithographic printing plate of  claim 1 , wherein the amount of the fluoro-aliphatic group-containing monomer (A) is in the range of 5 to 90% by weight on the basis of the total weight of the monomers constituting the fluorine atom-containing polymer and the weight average molecular weight of the fluorine atom-containing polymer ranges from 3,000 to 200,000. 
     
     
       7. The presensitized plate for preparing a lithographic printing plate of  claim 1 , wherein the amount of the fluorine atom-containing polymer ranges from 0.005 to 8% by weight on the basis of the amount of the light-sensitive resin composition for forming the light-sensitive layer. 
     
     
       8. The presensitized plate for preparing a lithographic printing plate of  claim 1 , wherein an additional monomer copolymerizable with the monomers (A) and (B) is used for the preparation of fluoro-aliphatic group-containing copolymer, which the additional monomer is selected from the group consisting of acrylic acid, methacrylic acid, acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers and vinyl esters. 
     
     
       9. A method for preparing a lithographic printing plate, which comprises imagewise exposing the presensitized plate of  claim 1  to light and then developing the exposed plate with a developer. 
     
     
       10. The method of  claim 9 , wherein the developer comprises (a) at least one saccharide selected from non-reducing saccharides and (b) at least one base and having a pH value ranging from 9.0 to 13.5.